/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.djmw.mouse.service.account;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import javax.annotation.PostConstruct;

import org.apache.commons.lang3.StringUtils;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authc.credential.HashedCredentialsMatcher;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.apache.shiro.util.ByteSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springside.modules.utils.Encodes;

import com.djmw.mouse.entity.LoginUseOnlyUser;
import com.djmw.mouse.entity.User;
import com.djmw.mouse.shiro.authc.UsernamePasswordRolesToken;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;

public class ShiroDbRealm extends AuthorizingRealm {

	protected LoginUseOnlyAccountService loginUseOnlyAccountService;
	protected static Map<String, AccountService> roleUserAccountServices;

	/**
	 * 认证回调函数，登录时调用。
	 */
	@Override
	protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authcToken) throws AuthenticationException {
		UsernamePasswordRolesToken token = (UsernamePasswordRolesToken) authcToken;
		LoginUseOnlyUser user = loginUseOnlyAccountService.findUserByLoginName(token.getUsername());
		if (user != null) {
			// 如果当前用户不属于登录所需要的角色则不予登录
			List<String> requiredRoles = ImmutableList.copyOf(StringUtils.split(token.getRequiredRoles(), ","));
			if (!user.getRoleList().containsAll(requiredRoles)) {
				throw new AuthenticationException("当前用户所属的角色与要求的角色不符。[登录名=" + user.getLoginName() + "][要求=" + token.getRequiredRoles() + "][所属=" + user.getRoles() + "]");
			}

			byte[] salt = Encodes.decodeHex(user.getSalt());
			return new SimpleAuthenticationInfo(new ShiroUser(user.getId(), user.getLoginName(), user.getName(), user.getRoles()),
					user.getPassword(), ByteSource.Util.bytes(salt), getName());
		} else {
			return null;
		}
	}

	/**
	 * 授权查询回调函数, 进行鉴权但缓存中无用户的授权信息时调用.
	 */
	@Override
	protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
		ShiroUser shiroUser = (ShiroUser) principals.getPrimaryPrincipal();
		LoginUseOnlyUser user = loginUseOnlyAccountService.findUserByLoginName(shiroUser.loginName);
		SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
		info.addRoles(user.getRoleList());
		return info;
	}

	/**
	 * 设定Password校验的Hash算法与迭代次数.
	 */
	@PostConstruct
	public void initCredentialsMatcher() {
		HashedCredentialsMatcher matcher = new HashedCredentialsMatcher(AccountService.HASH_ALGORITHM);
		matcher.setHashIterations(AccountService.HASH_INTERATIONS);

		setCredentialsMatcher(matcher);
	}

	@Autowired
	public void setLoginUseOnlyAccountService(LoginUseOnlyAccountService loginUseOnlyAccountService) {
		this.loginUseOnlyAccountService = loginUseOnlyAccountService;
	}

	@Autowired
	public void setRoleUserAccountServices(Map<String, AccountService> roleUserAccountServices) {
		ShiroDbRealm.roleUserAccountServices = roleUserAccountServices;
	}

	/**
	 * 自定义Authentication对象，使得Subject除了携带用户的登录名外还可以携带更多信息.
	 */
	public static class ShiroUser implements Serializable {
		private static final long serialVersionUID = -1373760761780840081L;
		public Long id;
		public String loginName;
		public String name;
		public String roles;
		private User user;

		public ShiroUser(Long id, String loginName, String name, String roles) {
			this.id = id;
			this.loginName = loginName;
			this.name = name;
			this.roles = roles;
		}

		public String getName() {
			return name;
		}

		/**
		 * 本函数输出将作为默认的<shiro:principal/>输出.
		 */
		@Override
		public String toString() {
			return loginName;
		}

		/**
		 * 重载hashCode,只计算loginName;
		 */
		@Override
		public int hashCode() {
			return Objects.hashCode(loginName);
		}

		/**
		 * 重载equals,只计算loginName;
		 */
		@Override
		public boolean equals(Object obj) {
			if (this == obj) {
				return true;
			}
			if (obj == null) {
				return false;
			}
			if (getClass() != obj.getClass()) {
				return false;
			}
			ShiroUser other = (ShiroUser) obj;
			if (loginName == null) {
				if (other.loginName != null) {
					return false;
				}
			} else if (!loginName.equals(other.loginName)) {
				return false;
			}
			return true;
		}

		public User getUser() {
			AccountService accountService = roleUserAccountServices.get(roles);
			if (accountService != null) {
				user = accountService.findUserByLoginName(loginName);
			}
			return user;
		}
	}
}
